Apply the labels of the previous email to the new email in the chain

[charlag]

As a user I want the new emails in the chain to be automatically labeled so that I do not lose track of labeled conversations.

AC

• When new email is added to the conversation it should have the same labels as the latest email in the conversation applied to it automatically
• There is a limit on number of labels that can be applied to a single email

Tasks

• Introduce a limit for applying labels to emails
• Handle the limit on the client if necessary
• Adjust creation of new emails to look up the latest email in the conversation, the labels from it and apply it

Tutadb: !714

Estimated: 24h
Time spent: 13h

Label limit per mail screenshots

Test notes

• There is a limit on number of labels that can be applied to a single email
  • On a new client
    • It is isn't possible to apply more labels than allowed per email (MAX_LABELS_PER_MAIL).
    • When applying labels to multiple mails at once (multiselect), the maximum is considered reached when at least one of the selected mails reaches the MAX_LABELS_PER_MAIL.
    • Removing applied and partially applied labels is possible even when max labels per mail is reached.
  • On an old client, applying more labels than allowed, is handled quietly and the labels that are above the max are just ignored.
    • Works with single mail.
    • Works with multiple mails at once (multiselect).
• When new email is added to the conversation it should have the same labels as the latest email in the conversation applied to it automatically.

[charlag]

Reviewed tutadb!714

[hrb-hub]

Merged tutadb!714